Application Of Electrical Resistivity Tomography Research Articles

Exploration on electrical resistance tomography in characterizing the slurry spatial distribution in cemented granular materials

AbstractThis study investigated the application of electrical resistance tomography (ERT) in characterizing the slurry spatial distribution in cemented granular materials (CGMs). For CGM formed by self-flow grouting, the voids in the accumulation are only partially filled and the bond strength is often limited, which results in difficulty in obtaining in situ samples for quality evaluation. Therefore, it is usually infeasible to evaluate the grouting effect or monitor the slurry spatial distribution by a mechanical method. In this research, the process of grouting cement paste into high alumina ceramic beads (HACB) accumulation is reliably monitored with ERT. It shows that ERT results can be used to calculate the cement paste volume in the HACB accumulation, based on calibrating the saturation exponent n in Archie’s law. The results support the feasibility of ERT as an imaging tool in CGM characterization and may provide guidance for engineering applications in the future.

Application of Electrical Resistivity Tomography to Assess the Impact of Reclamation of Low-Lying Areas by Fly Ash: A Case Study from Central India

Application of Electrical Resistivity Tomography to Assess the Impact of Reclamation of Low-Lying Areas by Fly Ash: A Case Study from Central India

Application of Electrical Resistivity Tomography in Geotechnical and Geoenvironmental Engineering Aspect

Electrical resistivity tomography (ERT) has turned out to be one of the most applied and user-friendly geophysical methods in geotechnical and geoenvironmental research. ERT is an emerging technology that is becoming popular nowadays for investigating subsurface conditions. Multiple attributes of the technology using various electrode configurations significantly reduce measurement time and are suitable for applications even in hardly accessible mountain areas. It is a noninvasive test for subsurface characterization and a very sensitive method used to determine geophysical properties, i.e., structural integrity, water content, fluid composition, etc. This paper aimed to elucidate the ERT technique’s main features and applications in geotechnical and geoenvironmental engineering through four case studies. The first case study investigated the possible flow paths and areas of moisture accumulation after leachate recirculation in a bioreactor landfill. The second case study attempted to determine the moisture variation along highway pavement. The third case study explored the slope failure investigation by ERT. The fourth case study demonstrated the efficiency of the ERT method in the landfill evapotranspiration (ET) cover to investigate moisture variation on a broader scale and performance monitoring. In all of the four cases, ERT exhibited promising performance.

Application of electrical resistivity tomography and geotechnical techniques for identification and characterization of collapsible soils in Bafoussam (Western, Cameroon)

Road failure catastrophes have increased in frequency in the West Cameroon area. The collapsed soil characteristics that contribute to these phenomena in Bafoussam have been investigated using the geophysical investigation combined with geotechnical tests. The result of electrical resistivity tomography shows water conditions and heterogeneity of road foundation materials: resistivity values higher than 200 Ωm indicate dry materials, values between 30 and 200 Ωm define wet materials, and values lower than 30 Ωm indicate the very wet or water-saturated materials. These water-saturated materials can therefore move, bounded by a sliding surface of high-resistivity materials. Geotechnical properties analysis shows that these materials are clayey-sensitive water (64% clay fraction; A-7-6), very plastic (liquid limit: 46–63% plasticity limit: 29–39%), compressible, with high porosity (e > 0.8), low shear strength, and high friction angle (24–37°). The quality of foundation materials associated with high slopes (> 40°) and heavy rainfall in wet seasons (July–October) means that seepage water is the main factor responsible for the mass movement observed on the road of Western Cameroon. The construction or rehabilitation of these roads should be carried out in compliance with the natural conditions of the project site.Article highlights- 2D Electrical Resistivity Tomography method is able to determine the nature, subsurface structure and water conditions of road foundation soils.- Geotechnical test can be used to define the physical and mechanical properties of road foundation soils.- These two techniques complement each other to understand the mass movement observed on two sections of road failures caused by seepage water.

Progress of Electrical Resistance Tomography Application in Oil and Gas Reservoirs for Development Dynamic Monitoring

Petroleum engineers need real-time understanding of the dynamic information of reservoirs and production in the development process, which is essential for the fine description of oil and gas reservoirs. Due to the non-invasive feature of electromagnetic waves, more and more oil and gas reservoirs have received attention to capture the development dynamics with electrical resistance tomography (ERT). By measuring the distribution of resistivity on the surface, the ERT can offer information on the subsurface media. The theory and foundation of the ERT technology are presented in this study in the context of monitoring oil and gas reservoir growth dynamics. The characteristics of ERT technology are analyzed, and the progress of ERT application in the development of monitoring dynamics in terms of residual oil distribution, detection of water-driven leading edge, and monitoring of fractures during hydraulic fracturing is reviewed, as well as the progress of ERT technology optimization, including forward and inverse algorithms. This review aims to promote further application of ERT in the field of reservoir dynamics monitoring because of its important engineering significance as well as its academic value in terms of improving production efficiency and reducing risk.

Application of electrical resistivity tomography (ERT) for vertical high-density polyethylene (HDPE) membrane detection

At landfill sites, uncontrolled leachate is a serious cause of groundwater and soil contamination at landfills and can occur extensively when there are looploopholesin the vertical HDPE (High-density polyethylene) membrane. For this reason, detecting HDPE membranes is necessary. The conventional electrode running poles approach is limited, it reflects the distribution of resistivity in 2D subsurface profiles, which is difficult to deploy electrodes above vertical HDPE membrane. According to the structural characteristics and field conditions of vertical HDPE membranes, the two-row current and potential (CP) electrode array is proposed to be applied to the testing of vertical HDPE membranes. The forward geoelectric model of the vulnerability was built using pyGimli, and data on 1519 apparent resistivity were acquired. The previous knowledge without the vulnerability was taken into consideration as the constraint condition, and the regional control was added to conduct the inversion, all using the least square approach. The model was used to analyze data on the detection of vertical HDPE membranes in a landfill In Yancheng, and potential flaws were discovered. Results show that the CP electrical measuring device can be efficient, quick, and accurate in the positioning of vertical HDPE membrane hole detection, and it is a cost-effective method. To verify the results, in the vertical HDPE membrane, through the Wenner device, the inversion of the 2D profile, and low resistivity anomalies are detected. This is thought to be through the leachate of leakage of HDPE membrane resistance rate is about 1.8 ohm. The findings demonstrate that the vertical HDPE membrane susceptibility may be located and detected using a CP electrical measuring instrument, which is a practical and efficient approach.

Application of Electrical Resistivity Tomography for the Assessment of Sinkhole Hazard to Improve Public Health and Safety Conditions on Post-Mining Lands

Application of Electrical Resistivity Tomography for the Assessment of Sinkhole Hazard to Improve Public Health and Safety Conditions on Post-Mining Lands

Electrical Resistivity Imaging for Identifying Critical Sulfate Concentration Zones Along Highways

Assessing sulfate concentration levels and their distributions within road alignments is crucial for the design of highway projects. Sulfate minerals in soils react with calcium-based additives, leading to sulfate-induced heaving and pavement failures. However, a reasonable assessment of the extent and levels of sulfate concentration using current practices, such as conventional laboratory-based methods, is still challenging because of the spatial heterogeneity of sulfate minerals and their seasonal fluctuations. This study aims to assess the application of electrical resistivity imaging (ERI) to determine levels and distributions of sulfate concentration. Finite element and least-squares optimization were used to process the data and generate subsurface inverted resistivity profiles. Fourteen ERI surveys were carried out for two sites with a potentially high risk of sulfate-induced heaving to help determine the extent of critical sulfate concentration zones. Laboratory tests (sulfate and moisture content tests) were conducted on ten samples collected from the field sites to validate ERI findings. The results showed that electrical resistivities of critical sulfate concentration zones are significantly lower than typical ranges of electrical resistivity of earth materials because of the abundance of salt ions in pore water, which facilitates the flow of electric current. The findings of this study were consistent with laboratory test results in determining the sulfate concentration levels. This study showed that ERI successfully provides a rapid and continuous assessment of critical sulfate concentration zones within highway alignments. The findings of this study will help materials and pavement engineers determine where alternative materials and pavement designs are needed.

Assessment of soil water content variability using electrical resistivity imaging in an Oxisol under conservation cropping systems

Agricultural systems are increasingly challenged of achieving high yields while optimizing plant water consumption. Soil conservation practices are preponderant in rain-fed agriculture for increasing water infiltration, water storage in the soil, and for promoting root development. This study aimed to assess the spatial-temporal soil water content (θ) dynamics identified by the application of electrical resistivity tomography (ERT) surveys in an Oxisol under grain production systems in the Brazilian Cerrado. The utilized cropping systems were: soybean monoculture (SS); maize monoculture (MM); maize/soybean rotation (MS); maize/soybean rotation with intercropped brachiaria (MBSB); maize/soybean rotation with high fertilizer investment (MS-HI), and MBSB and high fertilizer investment (MBSB-HI). ERT measurements were performed at field conditions using different time-steps during the rainy (March, 2019) and dry seasons (July 2018 and 2019). Logarithmic and power models were tested for evaluating the relationships between θ and the electrical resistivity (ρ). Results showed ERT was adequate for monitoring the spatial-temporal θ variation and for inferring soil-plant related processes (i.e., water uptake and macro-porosity due to roots development). The power model was more suitable in depicting the θ - ρ relationship, and for imaging the water unavailability for plants during the dry periods. Intercropped brachiaria positively affected the θ dynamics due to its aggressive root systems. MBSB-HI showed the highest θ values in the rainy season, demonstrating that ecological intensified cropping systems can help overcome severe dry spells, in the Brazilian Cerrado.

Application of Electrical Resistivity Imaging (ERI) to analyse geological structure in Paloh, Gua Musang, Kelantan

This study is conducted in Paloh, Gua Musang district, Kelantan and focussed on Electrical Resistivity Imaging (ERI) method which was carried out to assess the subsurface geological structures of Paloh area, Gua Musang. Two survey lines of 200 m are conducted in the study area by using Gradient array. The data obtained from ERI is processed by using RES2DINV software to produce a pseudosection model. Variable resistivity values ranging from 1Ωm to >3000Ωm with a depth of investigation of approximately 40m showed in the pseudosection model. Based on the model, the structural analysis of the study area resulted in several fault lines occurring in the subsurface area. The fault line indicated the occurrence of subsurface movement. This study suggests further geophysical investigation (seismic survey) be carried out as it would be able to give the extent of information on subsurface geological structures for geoengineering study for site investigation.

Near-Surface Geophysical Characterization of Lithologies in Corfu and Lefkada Towns (Ionian Islands, Greece)

Lefkada and Corfu old towns are located in the western part of Greece, in the Ionian Sea. Their proximity to the Hellenic subduction zone (HSZ) is the reason for their intense seismicity. The main goal of this study was the estimation of the geotechnical characteristics of the subsurface, with the contribution of applied geophysical techniques. Therefore, seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) were applied. A total of thirty-three (33) seismic and geoelectrical profiles were performed in both towns in order to evaluate the geotechnical characteristics of the subsurface formations. Additionally, subsurface resistivity distributions were investigated with the application of electrical resistivity tomography (ERT). Some important elastic moduli were calculated through the combination of estimated seismic wave velocities and laboratory density measurements. The horizontal distribution of seismic velocities and mechanical properties (σ, E, K, G) of Corfu town was illustrated in maps, for the depth of 5 m. The geophysical interpretation also revealed that Lefkada’s subsurface consists of only one compact geological formation, with little or no variation of its geophysical-geotechnical characteristics. Beyond that, the ground type classifications for the two towns were determined according to the European Committee for Standardization Eurocode 8, based on VS30 values.

Combined application of electrical resistivity tomography and multi-channel analysis of surface waves methods in the tunnel detection: A case study from Kocaeli University Campus Site, Turkey

In this study, two-dimensional electrical resistivity tomography (ERT) and one-dimensional multi-channel surface waves analysis (MASW) methods conducted on the surface were used to examine the location of a creek drainage tunnel constructed for the campus road and its relationship with the surrounding geological units in the Kocaeli University campus site results are presented. As it is known, geophysical studies conducted from the surface are generally applied in terms of feasibility and to determine the geological problems in the route of tunnels before the tunnel construction. Geophysical studies revealing the tunnel and associated underground characteristics in a completed tunnel are very limited. Therefore, this study aims to describe the general character of the tunnel and its surroundings in the subsurface, with measurements made by using surface geophysical methods (ERT and MASW) over the tunnel. In the ERT studies, four different arrays were examined to resolve this problem. These are, respectively; Wenner-alpha, −beta, −gamma and Schlumberger. On the tunnel problem here, a possible model similar to the geological structure dominated by the marl layers in the region was synthetically designed with these arrays. In this study, the effectiveness of all these arrays against the problem was tested. Then, by evaluating the data collected from the field, the appropriate array testing was examined for the real problem. In the context of these studies, the results of the MASW studies conducted between 24 and 46 m of the ERT line were compared with the ERT data to reveal the geological phenomena in the tunnel and its vicinity. The resistivity values (ρ) in the 2D electrical resistivity models obtained from ERT have values of ρ > 80 Ωm in the tunnel section and ρ < 55 Ωm in the materials surrounding the tunnel. The medium-high resistivity values characterize the earthfill layer. In MASW studies, it was revealed that shear wave velocity (Vs) values in the tunnel were lower (<250 m/s) and higher (250 and 500 m/s) in the materials surrounding the tunnel. Deep below the tunnel and in the northeastern part of the field, the ground has relatively higher shear wave velocities (Vs > 400 m/s). Because of the comparison of ERT and MASW results, it was revealed that both methods showed good agreement in terms of tunnel depth and size. While the different sequences used in the ERT study generally provided successful results in identifying the tunnel, different model results were revealed in the surrounding earthfill, weathered and intact marl layers. The MASW results, on the other hand, gave more successful results than expected in determining the location of the tunnel. Because of the comparison of both methods, it has been shown that the use of the ERT and MASW methods together can provide more effective results in examining the location of buried tunnels and their relationship with the surrounding geological units.

Application of electrical resistivity tomography (ERT) in uranium mining earth dam

Abstract Dams are built to contain water or mining tailings and provide several benefits to society. The safety and stability of these structures are essential since eventual accidents can generate catastrophic damage. The main cause of ruptures is associated with abnormal seepage, which can progress to an internal erosion process. To assess the stability and safety of dams, periodic inspections are carried out, which typically include visual inspections and geotechnical instrumentation. Some geophysical methods have the potential to assist conventional geotechnical instrumentation using non-destructive and rapid acquisition investigations. The present study applied a finite element forward modeling to evaluate the percolation conditions and water stability in an earth dam of a decommissioned uranium mine in Brazil. The dam is the final structure of the contention system of mine water treatment. The electrical resistivity data were acquired using electrical resistivity tomography (ERT) and Schlumberger array. The results were presented from the inversion of data in 3D models. The data were processed by open-source software (modeling and inversion of geophysical data). The results indicate the presence of water in the vertical filter located in the crest area. The different levels of investigation indicated water infiltration in the rock mass of the dam foundation. These results are supported by structural surveys carried out in the area that indicate a fracturing pattern in the rock mass of the mine area. The results of the study were satisfactory for the desired purposes and demonstrate that geophysical methods constitute an important complementary tool for the geotechnical monitoring dams.

Visualization investigation of defects in structural steel materials with electrical resistance tomography

A visualisation study of internal defects in structural steel was proposed using electrical resistance tomography (ERT) method. Structural steel is a metallic dielectric with low resistance and high conductivity. Therefore, the application of ERT in the field of low resistance, which is rarely involved, is of great significance. To realize this goal, in this study, we independently developed a 3D-ERT system with programmable logic control. In this system, based on to the actual condition, we construct a three-dimensional sensor to detect the defect location in structural steel. Numerical simulations and physical experiments of the three-dimensional sensor are conducted to test the effectiveness of the constructed system in detecting the location of structural steel defects. Numerical simulation and physical experimental results show that the 3D-ERT system can detect the location and approximate size of defects in structural steel. The research results show that this study not only provides a novel idea for non-destructive testing (NDT) of structural steel but also expands the application scope of ERT technology. Furthermore, the proposed NDT has broad development prospects and great application value.

Review of applications of electrical resistance tomography to chemical engineering

Abstract In spite of decades of study and investigation, the research on tomography and electrical resistance tomography (ERT) in particular, remains to be focus of immense scientific significance. ERT provides the ability to measure conductivity distribution inside a process plant and delivers time evolving multidimensional information. Such important and otherwise inaccessible information enhances critical process knowledge whilst improving the design and function of the process equipment. ERT has been employed in a variety of fields including chemical engineering. This paper reviews previous research carried out on the application of ERT within the chemical engineering arena. The applications are classified based on the objective of ERT measurements, the unit operations ERT has been utilized on, the media under examination, and also other technologies and data processing techniques used in combination with ERT. The objective of this taxonomy is to offer the reader with a broad insight into the current situation of ERT related research and developed applications in the chemical engineering field and to assist in the identification of research gaps for future investigation.

Application of Electrical Resistivity Tomography for Investigating the Internal Structure and Estimating the Hydraulic Conductivity of In Situ Single Fractures

Application of Electrical Resistivity Tomography for Investigating the Internal Structure and Estimating the Hydraulic Conductivity of In Situ Single Fractures

Emerging Trends and Hot Spots of Electrical Impedance Tomography Applications in Clinical Lung Monitoring.

ObjectiveThis study explores the emerging trends and hot topics concerning applications on electrical impedance tomography (EIT) in clinical lung monitoring.MethodsPublications on EIT applications in clinical lung monitoring in 2001–2021 were extracted from the Web of Science Core Collection (WoSCC). The search strategy was “electrical impedance tomography” and “lung.” CiteSpace, a VOS viewer was used to study the citation characteristics, cooperation, and keyword co-occurrence. Moreover, co-cited reference clustering, structural variation analysis (SVA), and future research trends were presented.ResultsSix hundred and thirty-six publications were included for the final analysis. The global annual publications on clinical lung monitoring gradually increased in the last two decades. Germany contributes 32.2% of total global publications. University Medical Center Schleswig-Holstein (84 publications, cited frequency 2,205), Physiological Measurement (105 publications, cited frequency 2,056), and Inéz Frerichs (116 articles, cited frequency 3,609) were the institution, journal, and author with the largest number of article citations in the research field. “Electrical impedance tomography” (occurrences, 304), “mechanical ventilation” (occurrences, 99), and “acute respiratory distress syndrome” (occurrences, 67) were the top most three frequent keywords, “noninvasive monitoring” (Avg, pub, year: 2008.17), and “extracorporeal membrane oxygenation” (Avg, pub, year: 2019.60) were the earliest and latest keywords. The keywords “electrical impedance tomography” (strength 7.88) and co-cited reference “Frerichs I, 2017, THORAX” (strength 47.45) had the highest burst value. “Driving pressure,” “respiratory failure,” and “titration” are the three keywords still maintaining a high brush value until now. The largest and smallest cluster of the co-cited references are “obstructive lung diseases” (#0, size: 97) and “lung perfusion” (#20, size: 5). Co-cited reference “Frerichs I, 2017, THORAX” (modularity change rate: 98.49) has the highest structural variability. Categories with most and least interdisciplinary crossing are “ENGINEERING” and “CRITICAL CARE MEDICINE.”ConclusionsEIT is a valuable technology for clinical lung monitoring, gradually converting from imaging techniques to the clinic. Research hot spots may continue monitoring techniques, the ventilation distribution of acute respiratory distress syndrome (ARDS), and respiratory therapy strategies. More diversified lung function monitoring studies, such as lung perfusion and interdisciplinary crossing, are potentially emerging research trends.

Application of ERT and SSR for geotechnical site characterization: A case study for resort assessment in New El Alamein City, Egypt

ABSTRACT The new city of El Alamein is one of the cities that the Egyptian government seeks to make it a tourist resort area that attract local and international tourism. This study examines how to apply geophysical methods to achieve soil study for foundational and construction purposes, especially near the seacoast. It also seeks to capture evidence of the presence of any clay lenses, as well as the intrusion of seawater into the shallow soil layers. The study uses two effective geophysical methods, the electrical resistivity tomography (ERT) and shallow seismic refraction (SSR). ERT method gained two layers, the appearance of seawater intrusion begins in the second layer. SSR method assigned the same two layers according to the seismic velocities with a thickness close to that determined by the ERT method. From seismic wave velocities, a set of geotechnical properties were calculated. From the integration of all the results, the study area divided into two zones; (1) cohesive soil zone is suitable for construction with low heights, provided that the architectural foundations are placed in the second layer, (2) loose soil and is affected by the intrusion of seawater, so it is not suitable for any construction purposes.

Groundwater Pathway Mapping Using Electrical Resistivity Tomography (ERT) Method

Geophysical electrical resistivity method has been one of the more popular non-destructive method to explore the subsurface. Geophysical electrical resistivity tomography (ERT) subsurface profiling was conducted to map the groundwater path along the embankment. The groundwater path able to decrease the slope stability, thus its need to locate the position for conduct the slope remediation via subsoil drainage. In this study, Terrameter LS2 model, electrodes, cables, battery, and cable connectors were the equipment used for measurement. This study uses cable spread line at 200m with 2.5m spacing between electrodes by using gradient protocol. The resistivity data was analyzed using RES2DINV software. The interpretation of groundwater path is based on the resistivity values less than 100 ohm.m, which is interpreted as saturated materials. This study demonstrates the efficiency of application of electrical resistivity tomography (ERT) in detecting the groundwater pathways. This investigation will help in sustaining the slope stability via indicating the position of groundwater pathways, and thus implementing the slope remediation work.

Indirect root distribution characterization using electrical resistivity tomography in different soil conditions

Root cohesion (Cv) represents a fundamental parameter for the stability of a tree as well as for the vegetation contribution to slope stability. Therefore, the finding of information concerning the root presence becomes mandatory to perform realistic predictions. A precise root detection is commonly practiced by a direct analysis of the root system carried out by digging trenches, via air-spade or extracting the entire root apparatus. This methods are very expensive, destructive and not replicable. This paper presents a 2D Electrical Resistivity Tomography (ERT) application in two study sites characterized by different soil textures and soil moisture conditions. The aims of this work were: i) to couple 2D resistivity profiles with high-resolution root density observations carried out along trenches for different soil texture and moisture contents; ii) to determine a regression law for the non-destructive estimation of the root distribution and the Mean Rooting Depth directly from ERT surveys for engineering purposes. The ERT was performed along transects diametrically crossing the root plate. Then, the direct detection of roots was carried out by digging trenches along the transects. The root distribution was coupled with the ERT observations and correlation laws were determined between ERT and root density. Finally, the capability of the obtained regressions in predicting the Mean Rooting Depth (MRD) was tested. Results confirm that soil electrical resistivity is influenced by the presence of the root systems, allowing the non-destructive root detection. Moreover, our findings suggested opposite responses for sandy and clayey soils under different soil moisture conditions. In particular, root detection in clayey soils appeared more efficient in wet conditions, while for sandy soils best results were obtained in dry conditions. The application of ERT for slope stability and tree stability analysis applications appeared promising for further applications both in urban and natural environments.